Please, please forgive me if this is common knowledge or if you've read this a hundred times before. I have read thousands of posts and not seen it mentioned once, and the search function is, well, not too swift. I know there are battery connection issues. I had them several times with my first Phantom Vision, which ran away and hid almost 3 months ago... the battery would dislodge slightly, and sometimes come out with even a minor mishap. I have no idea whether that was a factor in the mysterious tragic disappearance of P2V #1. You have to lift the backside of the battery as you insert it to make it go in evenly and get both the top clip and bottom clip to seat firmly with no gap. I've found it makes a significant difference and no more battery fall-out with P2V #2 or P2V+ #1. If you just let the battery ride the rails as you put it in, it can be on the rails but not seated right. When inserting the battery you have to neutralize the force of gravity by lifting up a little as you push the battery in.